Overhead power lines typically operate in a three-phase system, with each phase disposed on the pole or tower in spaced relation to the other two phases. A different power line is typically utilized for each different phase. U.S. Pat. No. 5,874,900, hereby incorporated herein by references, discloses an example of a three-phase power line system.
Utilities desire the ability to monitor the current and/or voltage in such power lines. There exists a need in the art for a more efficient system and/or method for monitoring current and/or voltage in such power lines. It is a purpose of this invention to fulfill this need, as well as other needs which will become apparent to those skilled in the art upon reviewing this document.
Generally speaking, certain example embodiments of this invention fulfill one or more of the above-listed needs by providing a method of sensing current, the method comprising:
providing a current sensing unit for a phase to be monitored;
the current sensing unit sensing a current of the phase and converting analog current data to digital current data;
forwarding the digital current data to a potential sensing unit via at least one optical interface; and
transmitting the digital current data from the potential sensing unit to a control unit via at least one communications interface.
Other example embodiments of this invention fulfill one or more of the above-listed needs by providing a system for simultaneously sensing current and voltage for a plurality of different phases, the system comprising:
a first current sensing unit and a first voltage sensing unit for a first power line to be monitored, wherein said first current sensing unit and said first voltage sensing unit communicate with one another optically;
said first current sensing unit mounted proximate a first end of a first high voltage insulator and said first voltage sensing unit mounted proximate a second end of said first high voltage insulator so that said first current sensing unit senses current of said first power line and said first voltage sensing unit senses voltage of said first power line;
a second current sensing unit and a second voltage sensing unit for a second power line to be monitored, wherein said second current sensing unit and said second voltage sensing unit communicate with one another optically;
said second current sensing unit mounted proximate a first end of a second high voltage insulator and said second voltage sensing unit mounted proximate a second end of said second high voltage insulator so that said second current sensing unit senses current of said second power line and said second voltage sensing unit senses voltage of said second power line;
a controller in communication with each of said first and second current sensing units and each of said first and second voltage sensing units; and
wherein said controller outputs sampling signals to each of said first and second current sensing units and each of said first and second voltage sensing units so that current and voltage measurements are simultaneously monitored in a common time relationship.